1. Field of the invention
The present invention relates to a vehicle braking force controller for detecting the actual deceleration of a vehicle and controlling the braking force of the vehicle to decrease the difference between the actual vehicle deceleration and a target deceleration value. For example, the present invention to a brake fluid pressure control means for unmanned vehicles which operate according to a predefined acceleration and deceleration pattern, with acceleration and deceleration remotely controlled, or with computer-controlled acceleration and deceleration, or to a brake fluid pressure control means for collision avoidance control based on the velocity of the controlled vehicle and the distance between the controlled vehicle and the vehicle therebefore.
2. Description of the prior art
The vehicle braking force control method of a vehicle collision avoidance system similar to the present invention is described in Japanese patent "kokai" number H5-105045 (1993-105045). In the vehicle braking force control method described therein, a deceleration value close to the actual vehicle deceleration is calculated by obtaining the average variance of the deceleration values calculated from plural sensors, including acceleration/deceleration sensors, to accurately control the fluid pressure of hydraulic brakes. It is therefore possible, by means of this method, to soften the braking shock before the vehicle stops.
This method, however, effectively controls the increase or decrease in the brake fluid pressure at a constant rate irrespective of the difference between the detected vehicle deceleration and the calculated target deceleration. The problem with this technique, therefore, is that the precision of braking force control can deteriorate or fluctuate, because a certain amount of time is required for control to take effect, and the constant rate of fluid pressure control can cause the actual vehicle deceleration to overshoot the target deceleration.